This finding from a new study is particularly concerning, given the rising rate of obesity in the U.S. Previous studies have shown that being obese during pregnancy increases your risk of diabetes and eclampsia, a potentially fatal problem for you and your unborn child.

Researchers from the University of Alabama at Birmingham wanted to find out if the crisis of obesity is also leading to more pregnancy and birthing problems.

They studied over 53,000 women who received prenatal care in the area. From 1980 to 1999, the average maternal weight at the first prenatal visit increased 20% from 144 pounds to 172 pounds. The number of women over 200, 250, and 300 pounds at this first visit also rose.

The study results are published in the October issue of the American Journal of Obstetrics and Gynecology.

This excess pregnancy weight does come at a price. The scientists found that as weight rose over the years, the number of women who developed diabetes during pregnancy also increased. This type of diabetes -- called gestational diabetes -- not only increases the chance of you going on to have full-blown diabetes later in life but can also cause problems with proper growth of your unborn child.

The frequency of large babies also increased. This might not seem like a particularly bad thing, but excessively large babies are more likely to have difficulty immediately after birth and are more likely to end up in the intensive care unit.

And finally, the researchers found that the number of C-sections has also continued to rise, a possible indication of problems surrounding delivery and birth. In fact, the number of C-sections due to obesity has tripled over the last 20 years.